Vasya became interested in bioinformatics. He's going to write an article about similar cyclic DNA sequences, so he invented a new method for determining the similarity of cyclic sequences.
Let's assume that strings $*s*$ and $*t*$ have the same length $*n*$, then the function $*h*(*s*, *t*)$ is defined as the number of positions in which the respective symbols of $*s*$ and $*t*$ are the same. Function $*h*(*s*, *t*)$ can be used to define the function of Vasya distance $ρ(*s*, *t*)$:

where

is obtained from string
s
, by applying left circular shift
i
times. For example,
$ρ("*AGC*", "*CGT*") =$
$*h*("*AGC*", "*CGT*") + *h*("*AGC*", "*GTC*") + *h*("*AGC*", "*TCG*") +$
$*h*("*GCA*", "*CGT*") + *h*("*GCA*", "*GTC*") + *h*("*GCA*", "*TCG*") +$
$*h*("*CAG*", "*CGT*") + *h*("*CAG*", "*GTC*") + *h*("*CAG*", "*TCG*") =$
$1 + 1 + 0 + 0 + 1 + 1 + 1 + 0 + 1 = 6$
Vasya found a string $*s*$ of length $*n*$ on the Internet. Now he wants to count how many strings $*t*$ there are such that the Vasya distance from the string $*s*$ attains maximum possible value. Formally speaking, $*t*$ must satisfy the equation:
.
Vasya could not try all possible strings to find an answer, so he needs your help. As the answer may be very large, count the number of such strings modulo $10^{9} + 7$.
Input
The first line of the input contains a single integer $*n*$ ($1 ≤ *n* ≤ 10^{5}$).
The second line of the input contains a single string of length $*n*$, consisting of characters "ACGT".
Output
Print a single number — the answer modulo $10^{9} + 7$.
Note
Please note that if for two distinct strings $*t*_{1}$ and $*t*_{2}$ values $ρ(*s*, *t*_{1})$ и $ρ(*s*, *t*_{2})$ are maximum among all possible $*t*$, then both strings must be taken into account in the answer even if one of them can be obtained by a circular shift of another one.
In the first sample, there is $ρ("*C*", "*C*") = 1$, for the remaining strings $*t*$ of length 1 the value of $ρ(*s*, *t*)$ is 0.
In the second sample, $ρ("*AG*", "*AG*") = ρ("*AG*", "*GA*") = ρ("*AG*", "*AA*") = ρ("*AG*", "*GG*") = 4$.
In the third sample, $ρ("*TTT*", "*TTT*") = 27$
样例
1
C
1
2
AG
4
3
TTT
1
题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。